The present invention relates in general to textile weaving looms and, particularly, to a selvage yarn feeding device for use in a weaving loom.
A selvage yarn feeding device to which the present invention appertains is composed of a pair of selvage yarn feeding units which are securely mounted on planet pinions, respectively, forming part of a planetary gear mechanism. The planet pinions respectively supporting the selvage yarn feeding units are arranged in diametrically opposed relationship to each other across a certain axis of revolution and are rotated, when the gear mechanism is in operation, about respective axes which are revolved about the above-mentioned axis of revolution. Each of the selvage yarn feeding units on the planet pinions includes a bobbin carrying a roll of selvage yarn wound thereon and a selvage yarn guide mechanism by way of which the selvage yarn leading from the roll on the bobbin is stepwise unwound from the bobbin and fed to the weaving shed of the loom. When the planet pinions are rotated about their own axes and revolved about the common center axis as above described, the bobbin and the selvage yarn guide mechanism of each of the selvage yarn feeding units on the planet pinions are rotated and revolved accordingly. In this instance, the direction of rotation of each of the planet pinions about its own axis is opposite to the direction in which the planet pinions are revolved about the common fixed axis and, for this reason, every point in the selvage yarn guide mechanism of each of the selvage yarn feeding units describes a quasi-elliptic curve which is symmetrical with respect to the axis of revolution of the planet pinions and which has a major axis passing axis. The yarn guide area in the selvage yarn guide mechanism of each of the selvage yarn feeding units is, therefore, moved into an "outermost rotational position" remotest from the common axis of revolution of the planet pinions every time the planet pinion supporting each of the selvage yarn feeding units makes a half turn about the axis of revolution. A representative example of a selvage yarn feeding device of the above described general nature is disclosed in Japanese Utility Model specification No. 43-18767.
When the selvage yarn unwound from the bobbin of each of the selvage yarn feeding units of the device thus arranged is passed through the yarn guide area in the associated selvage yarn guide mechanism, the selvage yarn which is kept taut between the yarn feeding unit and the weaving shed of the loom is forced to slide on various edge portions of the members constructing the yarn guide mechanism and are thus forcefully scraped against such edge portions. As a consequence, the selvage yarn tends to produce fibrous flues when being passed through the yarn guide area of the selvage yarn feeding unit. Such a tendency is pronounced when yarns spun from short fibers are used as the selvage yarns. The flues thus produced are deposited in the yarn guide area in the selvage yarn feeding unit and hinder the selvage yarn from being conveyed smoothly from the yarn feeding unit. This may cause the selvage yarn to break between the yarn feeding unit and the weaving shed of the loom.